1. Field of the Invention
The present invention relates to novel acyl acidic amino acid esters. The invention also relates to oily bases comprising such compounds, cosmetics comprising such oil bases, and processes for producing such compounds, oil bases, and cosmetics.
2. Discussion of the Background
Generally, various esters have been used as the oily raw material for skin and hair cosmetics and external medicine bases. A variety of sterol esters have conventionally been used as oily raw material that has excellent emulsifying performance. While sterol esters also have desirable moisture holding performance, there is a drawback that sterol esters impair the sensory feel of the product when mixed into cosmetics and external medicinal agents.
This problem is addressed in JP-A-3-275697 and Japanese Patent No. 2990624, which disclose long-chain acyl acidic amino acid sterol esters and long-chain acyl neutral amino acid sterol esters, respectively. However, the problem of impaired sensory feel is still present, and the stickiness problem also remains unsolved.
Silicone is generally known as an oil that has light feel. Modified silicones are also known that are produced by introducing various organic functional groups to impart characteristics. One known example of such silicone is the amino acid-introduced silicones (see JP-A-50-35119 and JP-A-50-158700). However, the sensory feel involves the friction feeling peculiar to silicone.
Sterol derivatives produced by binding this type of silicone to sterol that excels in moisture retention are also known (see JP-A-4-145097). However, sensory feel such as stickiness is still inferior, and material that provides excellent sensory feel, such as non-greasy and non-sticky feeling, while maintaining moisture retention is not available.